Support for multiple Java Development Kits (JDKs)

The IBM® i platform supports multiple versions of the Java™ Development Kits (JDKs) and the Java 2 Platform, Standard Edition.

Note: In this documentation, depending on the context, the term JDK refers to any supported version of the JDK or the Java 2 Platform, Standard Edition (J2SE). Usually, the context in which JDK occurs includes a reference to the specific version and release number.

IBM i supports using multiple JDKs simultaneously, but only through multiple Java virtual machines. A single Java virtual machine runs one specified JDK. You can run one Java virtual machine per job.

Find the JDK that you are using or want to use, and select the coordinating option to install. See Installing Java on your IBM i server to install more than one JDK at one time.

When using IBM Technology for Java, you select which 5770-JV1 option to run (and therefore which JDK/bit mode) by setting the JAVA_HOME environment variable. Once a Java virtual machine is up and running, changing the JAVA_HOME environment variable has no effect.

The following table lists the supported options for this release.

Start of change
5770-JV1 options JAVA_HOME
Option 16 - IBM Technology for Java 8 32-bit /QOpenSys/QIBM/ProdData/JavaVM/jdk80/32bit
Option 17- IBM Technology for Java 8 64-bit /QOpenSys/QIBM/ProdData/JavaVM/jdk80/64bit
  • Option 14 - IBM Technology for Java 71 32-bit
  • Option 14 - IBM Technology for Java 7 32-bit
  • /QOpenSys/QIBM/ProdData/JavaVM/jdk71/32bit
  • /QOpenSys/QIBM/ProdData/JavaVM/jdk70/32bit
  • Option 15 - IBM Technology for Java 71 64-bit
  • Option 15 - IBM Technology for Java 7 64-bit
  • /QOpenSys/QIBM/ProdData/JavaVM/jdk71/64bit
  • /QOpenSys/QIBM/ProdData/JavaVM/jdk70/64bit
End of change

The default JDK chosen in this multiple JDK environment depends on which 5770-JV1 Options are installed. The following table gives some examples. You can access IBM Technology for Java JDKs by setting the JAVA_HOME environment variable, or by specifying a fully qualified path to the Java tool or utility located in the JDK you want to use.

Start of change
Install Enter Result
All supported options are installed java QIBMHello 8.0 32-bit is used
Option 14 (7&7.1 32-bit) and Option 15(7&7.1 64-bit) java QIBMHello 7.1 32-bit is used
End of change
Note: If you install only one JDK, the default JDK is the one you installed. If you install more than one JDK, the following order of precedence determines the default JDK:Start of change
  1. Option 16 - IBM Technology for Java 8.0 32-bit
  2. Option 17 - IBM Technology for Java 8.0 64-bit
  3. Option 14 - IBM Technology for Java 7.1 32-bit
  4. Option 15 - IBM Technology for Java 7.1 64-bit
  5. Option 14 - IBM Technology for Java 7.0 32-bit
  6. Option 15 - IBM Technology for Java 7.0 64-bit
End of change